Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

418
FXUS63 KLOT 122321
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
521 PM CST Thu Feb 12 2026

.KEY MESSAGES...

- Temperatures will remain generally above average through the
  upcoming 7 days.

- Aside from a chance for rain well south of I-80 Saturday
  night, primarily dry weather is in store until precipitation
  chances return midweek next week.

&&

.DISCUSSION...
Issued at 245 PM CST Thu Feb 12 2026

An early spring-like weather pattern will set up over the next
week for the region, favoring above to at times well above
normal temperatures, though with variability in the details.

Tonight through Saturday Night:

Tonight will feature above average but relatively chilly
temperatures (20s) as surface high pressure slowly shifts
eastward. Friday will the warmest day for the area as a whole
since back prior to the 3-week long cold stretch from mid
January into the start of this month. With no snow cover, plenty
of sunshine, modestly breezy southwest winds (especially
southeast 1/2 to 2/3 of the area), and sub-freezing dew points,
setup looks prime for temps in range of the warmest guidance.
This supported highs in the low-mid 50s in the grids. Decent
radiational cooling Friday night coming off the mild afternoon
will yield lows in the upper 20s to lower 30s.

On Saturday, east-southeast winds along the Illinois shore will
result in notably cooler temps (low 40s) than on Friday. Away
from the IL shore, our forecast highs are similar to those of
Friday, though mid and high level overcast may keep things a bit
cooler than currently depicted. A southern stream short-wave
will track well south of our area this weekend. Rain on the
northern periphery of the system would reach into areas well
south of I-80 (primarily near/south of the IL and Kankakee
Rivers) Saturday evening and overnight if the consistently
farther north ECMWF/EPS mean solution comes to fruition.
Meanwhile, most of the remainder of the guidance has continued
to favor even southern sections remaining dry. Even in a EC/EPS
scenario, there likely would be a very sharp cut-off north of
wherever the northern periphery of the rain sets up. As such, a
gradient from ~40-50% PoPs south of US-24 to less than 15%
near/north of I-80 appears reasonable.

Sunday through Thursday:

Sunday will be another unseasonably mild day away from Lake
Michigan, reaching the mid to locally upper 50s. A lake breeze
shifting inland during the afternoon will limit highs to the
upper 40s to lower 50s near the lake, cooling to the low-mid 40s
behind the lake breeze. Following a mild Sunday night (low-mid
30s), Monday looks quite mild based on progged 925 mb to 850 mb
temps, though mid and high cloud cover may keep things in
check, relatively speaking, with the official forecast (mid-
upper 50s) still about 20 degrees above average. The question
into Tuesday is whether a weak cold front pushes takes on
backdoor characteristics and settles southward, which will have
large implications on temperatures, especially closer to the lake.

The main weather of interest next week will come Wednesday
through Thursday as trough ejection from the southwest results
in broad lee cyclogenesis over the central and northern High
Plains. As is to be expected, there`s plenty of uncertainty in
the regarding the specific evolution of key features at the
surface and aloft. The position and trajectory of the
dominant/consolidated surface low will determine how much of the
area gets into the exceptionally mild warm sector on Wednesday
(highs well into the 60s). Precipitation wise, showers (with a
non-zero chance for elevated convection) are possible near or
north of the system warm front Tuesday night into Wednesday
morning.

A cold front should move across the area sometime on Wednesday,
knocking temps down some on Thursday. Details are quite muddy
late in the workweek, with a signal for a follow-up short-wave
that may arrive as early as Wednesday night into Thursday. Note
that any deeper synoptic system later next week will likely have
well above average moisture content to work with, problematic
for any areas that see heavy rain on top of thawing out but
still frozen ground. Given the large ensemble spread, PoPs on
Thursday are only in the 20-30% range for now.

Castro

&&

.AVIATION /00Z TAFS THROUGH 06Z SATURDAY/...
Issued at 520 PM CST Thu Feb 12 2026

No significant aviation weather concerns for the 00Z TAFs.

Weak surface high pressure will drift off to the east of the
terminals tonight, with a period of light/variable winds
(easterly with a slight lake breeze enhancement this evening for
ORD/MDW). With the surface high east of the area Friday, winds
will turn southwesterly around 10 kts with a few gusts into the
mid-upper teens possible during the afternoon. Any gusts should
end with sunset Friday evening. Otherwise, VFR, mainly clear
conditions are expected throughout the forecast period.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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